ENFI
Zinc and the Copper Problem

Zinc and the Copper Problem

Central to immunity, healing and hormone synthesis — and in direct competition with copper for absorption, which is why sustained high doses create a new deficiency.

Zinc is one of the more useful minerals to supplement and one of the easiest to get wrong, because the failure mode does not look like a zinc problem.

What it does

  • Required by hundreds of enzymes, including those involved in DNA repair and protein synthesis
  • Central to immune function — the basis for its use at the onset of a cold, where the evidence is modest but real if taken early enough
  • Necessary for testosterone synthesis; deficiency reliably lowers it, though supplementing above sufficiency does not raise it further
  • Involved in taste and smell, which is why losing them is a classic deficiency sign
  • Required for skin integrity and wound healing

The copper competition

Zinc and copper are absorbed by the same transporters. High zinc intake induces a protein in the gut that binds copper and carries it out with the shed cells. Take 50 mg of zinc daily for a few months and you can produce a genuine copper deficiency — which presents as anaemia that does not respond to iron, and in severe cases as neurological symptoms.

Long-term high-dose zinc without copper is one of the few supplement regimes that reliably causes harm in otherwise healthy people. It is also widely recommended.

Doing it sensibly

  • 15–30 mg daily is enough for ongoing use. This is the range where the copper issue does not arise
  • If taking more than 30 mg for longer than a few weeks, add copper at roughly a 15:1 zinc-to-copper ratio
  • Short high-dose use at the start of a cold — 75 mg or so as lozenges for a few days — is a different situation and does not require the same caution
  • Take with food. Zinc on an empty stomach causes nausea in a large proportion of people
  • Separate from iron and calcium supplements, which compete for the same absorption

Who is likely to be low

Vegetarians and vegans, because plant zinc is bound to phytates and poorly absorbed. People with inflammatory bowel conditions. Heavy drinkers. Older adults, in whom absorption declines. And anyone on long-term high-dose supplemental iron, for the same competition reason described above, running the other way.

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